57c4b1bdc2
This is first in series of changes that provides separation of flows into engines and pattens. Patterns define structure, while engine define how the task should be run according to said structure. This change adds the basic patterns and a very simple engine that is able to run flow defined with patterns by converting it to recursive structure of so-called 'actions'. For simplicity and ease of review certain major features like resumption, saving and passing on task results and notifications are left out for farther changes. Partially implements blueprint patterns-and-engines Co-authored-by: Anastasia Karpinska <akarpinska at griddynamics.com> Change-Id: I68515d8a5b30d5d047bf9beb67cc3e2111175190
59 lines
1.8 KiB
Python
59 lines
1.8 KiB
Python
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# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from taskflow.engines.action_engine import seq_action
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from taskflow.engines.action_engine import task_action
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from taskflow import blocks
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from taskflow import states
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class ActionEngine(object):
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"""Generic action-based engine
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Converts the flow to recursive structure of actions.
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"""
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def __init__(self, flow, action_map):
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self._action_map = action_map
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self._root = self._to_action(flow)
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def _to_action(self, pattern):
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try:
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factory = self._action_map[type(pattern)]
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except KeyError:
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raise ValueError('Action of unknown type: %s (type %s)'
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% (pattern, type(pattern)))
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return factory(pattern, self._to_action)
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def run(self):
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status = self._root.execute(self)
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if status == states.FAILURE:
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self._root.revert(self)
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class SingleThreadedActionEngine(ActionEngine):
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def __init__(self, flow):
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ActionEngine.__init__(self, flow, {
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blocks.Task: task_action.TaskAction,
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blocks.LinearFlow: seq_action.SequentialAction,
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blocks.ParallelFlow: seq_action.SequentialAction
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})
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